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• Auto configures and runs the embedded gRPC server with @GrpcService-enabled beans as part of your spring-boot application

• Automatically creates and manages your grpc channels and stubs with @GrpcClient

• Supports Spring Cloud (register services to Consul or Eureka and fetch gRPC server information)

• Supports Spring Sleuth to trace application

• Supports global and custom gRPC server/client interceptors

• Spring-Security support

• Automatic metric support (micrometer/actuator based)

• Also works with grpc-netty-shaded

2.x.x.RELEASE support Spring Boot 2 & Spring Cloud Finchley.

The latest version: 2.1.0.RELEASE

1.x.x.RELEASE support Spring Boot 1 & Spring Cloud Edgware, Dalston, Camden.

The latest version: 1.4.1.RELEASE

Note: This project can also be used without Spring-Boot, however that requires some manual bean configuration.

To add a dependency using Maven, use the following:

<dependency>
  <groupId>net.devh</groupId>
  <artifactId>grpc-spring-boot-starter</artifactId>
  <version>2.1.0.RELEASE</version>
</dependency>

To add a dependency using Gradle:

dependencies {
  compile 'net.devh:grpc-spring-boot-starter:2.1.0.RELEASE'
}

To add a dependency using Maven, use the following:

<dependency>
  <groupId>net.devh</groupId>
  <artifactId>grpc-server-spring-boot-starter</artifactId>
  <version>2.1.0.RELEASE</version>
</dependency>

To add a dependency using Gradle:

dependencies {
  compile 'net.devh:grpc-server-spring-boot-starter:2.1.0.RELEASE'
}

Annotate your server interface implementation(s) with @GrpcService

@GrpcService
public class GrpcServerService extends GreeterGrpc.GreeterImplBase {

    @Override
    public void sayHello(HelloRequest req, StreamObserver<HelloReply> responseObserver) {
        HelloReply reply = HelloReply.newBuilder().setMessage("Hello ==> " + req.getName()).build();
        responseObserver.onNext(reply);
        responseObserver.onCompleted();
    }

}

By default, the grpc server will listen to port 9090. These and other settings can be changed via Spring's property mechanism. The server uses the grpc.server. prefix.

grpc.server.port=9090
grpc.server.address=0.0.0.0

This library supports securing the grpc application with Spring-Security. You only have to add Spring-Security (core or config) to your dependencies and then configure it as needed.

• BasicAuth

  @Bean
  AuthenticationManager authenticationManager() {
      final List<AuthenticationProvider> providers = new ArrayList<>();
      providers.add(...); // Possibly DaoAuthenticationProvider
      return new ProviderManager(providers);
  }
  
  @Bean
  GrpcAuthenticationReader authenticationReader() {
      final List<GrpcAuthenticationReader> readers = new ArrayList<>();
      readers.add(new BasicGrpcAuthenticationReader());
      return new CompositeGrpcAuthenticationReader(readers);
  }

• Certificate Authentication

  @Bean
  AuthenticationManager authenticationManager() {
      final List<AuthenticationProvider> providers = new ArrayList<>();
      providers.add(new X509CertificateAuthenticationProvider(userDetailsService()));
      return new ProviderManager(providers);
  }
  
  @Bean
  GrpcAuthenticationReader authenticationReader() {
      final List<GrpcAuthenticationReader> readers = new ArrayList<>();
      readers.add(new SSLContextGrpcAuthenticationReader());
      return new CompositeGrpcAuthenticationReader(readers);
  }

  and some properties:

  grpc.server.security.enabled=true
  grpc.server.security.certificateChainPath=certificates/server.crt
  grpc.server.security.privateKeyPath=certificates/server.key
  grpc.server.security.trustCertCollectionPath=certificates/trusted-clients-collection
  grpc.server.security.clientAuth=REQUIRE

• Chain multiple mechanisms by using the CompositeGrpcAuthenticationReader class

• Your own authentication mechanism (Implement a GrpcAuthenticationReader yourself)

• Via Spring-Security's annotations

  @Configuration
  @EnableGlobalMethodSecurity(proxyTargetClass = true, ...)
  public class SecurityConfiguration {

  proxyTargetClass is required, if you use annotation driven security!
  However, you will receive a warning that MyServiceImpl#bindService() method is final.
  You cannot avoid that warning (without massive amount of work), but it is safe to ignore it.
  The #bindService() method uses a reference to this, which will be used to invoke the methods.
  If the method is not final it will delegate to the original instance and thus it will bypass any security layer that you intend to add, unless you re-implement the #bindService() method on the outermost layer (which Spring does not).

• Via manual configuration

  @Bean
  AccessDecisionManager accessDecisionManager() {
      final List<AccessDecisionVoter<?>> voters = new ArrayList<>();
      voters.add(new AccessPredicateVoter());
      return new UnanimousBased(voters);
  }
  
  @Bean
  GrpcSecurityMetadataSource grpcSecurityMetadataSource() {
      final ManualGrpcSecurityMetadataSource source = new ManualGrpcSecurityMetadataSource();
      source.set(MyServiceGrpc.getSecureMethod(), AccessPredicate.hasRole("ROLE_USER"));
      source.setDefault(AccessPredicate.permitAll());
      return source;
  }

To add a dependency using Maven, use the following:

<dependency>
  <groupId>net.devh</groupId>
  <artifactId>grpc-client-spring-boot-starter</artifactId>
  <version>2.1.0.RELEASE</version>
</dependency>

To add a dependency using Gradle:

dependencies {
  compile 'net.devh:grpc-client-spring-boot-starter:2.1.0.RELEASE'
}

There are three ways to get a connection to the gRPC server:

• Use grpcChannelFactory.createChannel(serverName) to create a Channel and create the grpc stub yourself.

  @Autowired
  private GrpcChannelFactory grpcChannelFactory;
  
  private GreeterGrpc.GreeterBlockingStub greeterStub;
  
  @PostConstruct
  public void init() {
      Channel channel = grpcChannelFactory.createChannel("gRPC server name");
      greeterStub = GreeterGrpc.newBlockingStub(channel);
  }

• Annotate a field of type Channel with @GrpcClient(serverName) and create the grpc stub yourself.

  • Do not use in conjunction with @Autowired or @Inject

  @GrpcClient("gRPC server name")
  private Channel channel;
  
  private GreeterGrpc.GreeterBlockingStub greeterStub;
  
  @PostConstruct
  public void init() {
      greeterStub = GreeterGrpc.newBlockingStub(channel);
  }

• Annotate a field of your grpc client stub with @GrpcClient(serverName)

  • Do not use in conjunction with @Autowired or @Inject

  @GrpcClient("gRPC server name")
  private GreeterGrpc.GreeterBlockingStub greeterStub;

Note: You can use the same grpc server name for multiple channels and also different stubs (even with different interceptors).

Then you can send queries to your server just like this:

HelloReply response = stub.sayHello(HelloRequest.newBuilder().setName(name).build());

By default, the client assumes that the server runs on 127.0.0.1 with port 9090. These and other settings can be changed via Spring's property mechanism. The clients use the grpc.client.(serverName). prefix.

grpc.client.(gRPC server name).host[0]=127.0.0.1
grpc.client.(gRPC server name).port[0]=9090
# Or
grpc.client.myName.host=127.0.0.1
grpc.client.myName.port=9090

There are multiple ways for the client to authenticate itself. Currently only the following are supported:

• BasicAuth

  Using a ClientInterceptor (other authentication mechanisms can be implemented in a similar fashion).

  @Bean
  ClientInterceptor basicAuthInterceptor() {
      return AuthenticatingClientInterceptors.basicAuth(username, password);
  }

  • For all clients the same credentials

    @Bean
    public GlobalClientInterceptorConfigurer basicAuthInterceptorConfigurer() {
        return registry -> registry.addClientInterceptors(basicAuthInterceptor());
    }

  • Different credentials per client

    @GrpcClient(value = "myClient", interceptorNames = "basicAuthInterceptor")
    private MyServiceStub myServiceStub;

• Certificate Authentication

  Only needs some configuration properties:

  #grpc.client.test.security.authorityOverride=localhost
  #grpc.client.test.security.trustCertCollectionPath=certificates/trusted-servers-collection
  grpc.client.test.security.clientAuthEnabled=true
  grpc.client.test.security.certificateChainPath=certificates/client.crt
  grpc.client.test.security.privateKeyPath=certificates/client.key

This library also supports grpc-netty-shaded which might prevent conflicts with incompatible grpc-versions or conflitcts between libraries that require different versions of netty.

Note: If the shaded netty is present on the classpath, then this library will always favor it over the normal grpc-netty one.

You can use it with Maven like this:

<dependency>
    <groupId>io.grpc</groupId>
    <artifactId>grpc-netty-shaded</artifactId>
    <version>${grpcVersion}</version>
</dependency>

<!-- For both -->
<dependency>
    <groupId>net.devh</groupId>
    <artifactId>grpc-spring-boot-starter</artifactId>
    <version>...</version>
    <exclusions>
        <exclusion>
            <groupId>io.grpc</groupId>
            <artifactId>grpc-netty</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<!-- For the server -->
<dependency>
    <groupId>net.devh</groupId>
    <artifactId>grpc-server-spring-boot-starter</artifactId>
    <version>...</version>
    <exclusions>
        <exclusion>
            <groupId>io.grpc</groupId>
            <artifactId>grpc-netty</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<!-- For the client -->
<dependency>
    <groupId>net.devh</groupId>
    <artifactId>grpc-client-spring-boot-starter</artifactId>
    <version>...</version>
    <exclusions>
        <exclusion>
            <groupId>io.grpc</groupId>
            <artifactId>grpc-netty</artifactId>
        </exclusion>
    </exclusions>
</dependency>

and like this when using Gradle:

compile "io.grpc:grpc-netty-shaded:${grpcVersion}"

compile 'net.devh:grpc-spring-boot-starter:...' exclude group: 'io.grpc', module: 'grpc-netty' // For both
compile 'net.devh:grpc-client-spring-boot-starter:...' exclude group: 'io.grpc', module: 'grpc-netty' // For the client
compile 'net.devh:grpc-server-spring-boot-starter:...' exclude group: 'io.grpc', module: 'grpc-netty' // For the server

Read more about our example projects here.

Before you begin to dive into the details, make sure that the grpc and netty library versions are compatible with each other. This library brings all necessary dependencies for grpc and netty to work together. In some cases, however, you may need additional libraries such as tcnative or have other dependencies that require a different version of netty, which may cause conflicts. grpc-java has a table which shows compatible version combinations. As an alternative, you can replace the netty libraries with grpc-netty-shaded.

• java.lang.IllegalStateException: Failed to load ApplicationContext
• Caused by: org.springframework.context.ApplicationContextException: Failed to start bean 'grpcServerLifecycle'
• Caused by: java.lang.IllegalStateException: Could not find TLS ALPN provider; no working netty-tcnative, Conscrypt, or Jetty NPN/ALPN available

or

• AbstractMethodError: io.netty.internal.tcnative.SSL.readFromSSL()

or

• javax.net.ssl.SSLHandshakeException: General OpenSslEngine problem

You don't have the (correct) library or version of netty-tcnative... in your classpath.

(There is a breaking change between netty 4.1.24.Final -> 4.1.27.Final and netty-tcnative 2.0.8.Final -> 2.0.12.Final and also elsewhere)

See also grpc-java: Security.

By default, the grpc client assumes that the server uses TLS and will try to use a secure connection. During development and for tests is it unlikely that the required certificates are available thus you have to switch to PLAINTEXT connection mode.

grpc.client.(gRPC server name).negotiationType=PLAINTEXT

Note: The grpc protocol and we strongly recommend using TLS for production use.

Sometimes you just want to launch your application in your test to test the interaction between your services. This will also start the grpc server, however it won't be shut down after each test (class). You can avoid that issue by adding @DirtiesContext to your test classes or methods.

• io.grpc.StatusRuntimeException: UNAVAILABLE: io exception
• Caused by: javax.net.ssl.SSLHandshakeException: General OpenSslEngine problem
• Caused by: java.security.cert.CertificateException: No name matching gRPC server name found

The name of the gRPC server name in the client config does not match the common / alternative name in the server certificate. You have to configure the grpc.client.(gRPC server name).security.authorityOverride property with a name that is present in the certificate.

Contributions are always welcomed! Please see CONTRIBUTING.md for detailed guidelines.

https://github.com/yidongnan/grpc-spring-boot-starter/tree/master/examples